JavaScript (ES2026) reference · String Methods

JavaScript String toLowerCase() Method

Return the string converted to lowercase. Use it for case-insensitive comparisons.

JavaScript (ES2026) Since ES1

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Syntax

string.toLowerCase()

A new string.

LowercaseTry it yourself

console.log("Hello World".toLowerCase());

Output

hello world

Compare ignoring caseTry it yourself

const a = "[email protected]", b = "[email protected]";
console.log(a === b, a.toLowerCase() === b.toLowerCase());

Output

false true

Version	Change
JavaScript ES1	Added

string.toUpperCase() · Return the string converted to uppercase letters. Use toLocaleUpperCase() for language-specific rules.
string.toLocaleLowerCase() · Convert to lowercase using a language's rules, which matters for languages like Turkish.
string.localeCompare() · Compare two strings using language rules; returns a negative number, 0 or a positive number. Use it to sort names.
JavaScript Strings · tutorial
JavaScript String Methods · tutorial